You’ve probably seen one glowing ominously on social media and wondered whether it was serious skincare technology or simply an expensive way to look like a futuristic serial killer. But LED face masks aren’t merely another bathroom gadget. They use specific wavelengths of light to address concerns such as fine lines, inflammation and breakouts, bringing a treatment once reserved for dermatologists’ offices and high-end facials into your nightly routine.

The science sounds complicated, but the basic idea is pretty straightforward. Red and near-infrared light are generally used to support collagen production, calm inflammation and improve the appearance of aging skin. Blue light targets acne-causing bacteria and can be especially useful around breakout-prone areas, including beneath facial hair. We can promise you that they work. The only catch is that results require consistency. Even the most advanced mask you use twice before abandoning in a drawer won’t do much for your complexion.

That makes comfort, treatment length and ease of use nearly as important as the lights themselves. Some masks require only three minutes a day, while others add cooling or massage to make the ritual a little more rewarding. And because quality varies considerably, experts advise choosing an FDA-cleared device rather than relying on vague phrases such as “FDA-listed” or “FDA-registered.” We scoured the market and strapped on a lot of masks to determine how much technology—and how much mask—you actually need.